Service difficulty report · Alternator · Cessna 404

Difficulty date
April 3, 2014
Submitted
April 23, 2014
Operation
Air carrier
Aircraft
N550MA
Make and model
Cessna 404
Aircraft serial
4040443
Aircraft time
14,959 hours, 14,907 cycles
Engine
Cont GTSIO520C
Engine time
1,077 hours, 1,077 cycles
Propeller
Mcauly 3FF32C501
Part
Alternator
Part number
ALV9510
Part serial
G124224
Condition
Failed
Location
Right
Part time
1,961 hours, 1,911 cycles
Stage of operation
CR
How discovered
O
Nature of condition
H, J
Precautionary procedure
A

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

THE ACFT HAD TOTAL ELECTRICAL FAILURE DURING FLIGHT, DUE TO BOTH CHARGING SYSTEMS FAILING TOGETHER. RT ALTERNATOR FAILED DURING CRUISE, SHORTLY AFTER LT ALTERNATOR FAILED DUE TO A FAILED DRIVE CLUTCH. THE RT ALTERNATOR APPEARED TO HAVE AN INTERNAL SHORT THAT CAUSED A SUDDEN POWER SPIKE TO GO THRU THE WIRING TO THE REGULATOR. THE SUDDEN SPIKE CAUSED BOTH REGULATORS TO FAIL ALSO. THE ACFT DIVERTED FROM IT'S PLANNED AIRPORT FOR LANDING TO ANOTHER AIRPORT DUE TO WEATHER AND NO ELECTRICAL POWER. THE PILOT USED THE EMERGENCY GEAR BLOWDOWN SYS TO PUT THE GEAR DOWN AND LOCKED AND PROCEED TO LAND THE ACFT SAFELY AT THE ALTERNATE AIRPORT WITHOUT ANY ADDITIONAL ISSUES. THE MECHANIC ON STATION REMOVED THE ALTERNATOR AND REPORTED THAT IT HAD A BURNED SMELL. HE REPLACED THE ALTERNATOR, DRIVE CLUTCH, BATTERY AND BOTH REGULATORS. INSPECTED THE WIRING GOING INTO THE ACFT FOR ANY SIGNS OF DAMAGE, NONE WAS FOUND. PROCEED TO PERFORM A GROUND RUN UP AND SYSTEM CHECK. ALL SYSTEMS OPERATED AS DESIGNED AND WITHIN LIMITS.

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